[Amino acid sequence of anionic protease inhibitors from buckwheat seeds]

Complete amino acid sequence of IT1 protease inhibitor and partial amino acid sequences of IT2 and IT4 protease inhibitors from buckwheat Fagopyrum esculentum Moench seeds were determined by automatic Edman degradation and mass spectrometry. IT1 inhibitor comprises 69 amino acid residues and its molecular mass is 7743.8 D. N-terminal 48 amino acid residues of IT2 inhibitor are identical to similar sequence of IT1 inhibitor. The sequence of 10 amino acid residues of IT4 inhibitor is completely identical to a part of the sequence of IT1 inhibitor C-terminally adjacent to its active site. Analysis of amino acid sequences of IT1, IT2 and IT4 inhibitors suggests that the proteins are the members of the potato proteinase inhibitor 1 family and include Arg-Asp residues in their active site.